We take into account a fee buffer of twice the current fee rate
of the commitment transaction plus an additional htlc output
when we are the opener of the channel hence pay when publishing the
commitment transaction. This buffer is not consensus critical
because we only consider it when we are in control of adding a
new htlc to the state. The goal is to prevent situations
where we push our local balance below our channel reserve due to
parallel adding of htlcs to the state. Its not a panacea for these
situations but until we have __option_simplified_update__ deployed
widely on the network its a good precaution to protect against
fee spikes and parallel adding of htlcs to the update log.
Moreover the way the available balance for a channel changed.
We now need to account for a fee buffer when we are the channel
opener. Therefore all the tests had to be adopted.
In this commit, we add a new NewCommitState struct. This preps us for
the future change wherein a partial signature is also added to the mix.
All related tests and type signatures have also been updated
accordingly.
In this commit, we extract the musig2 session management into a new
module. This allows us to re-use the session logic elsewhere in unit
tests so we don't need to instantiate the entire wallet.
Add a new test htlc set comprised of htlc 1 from the original set and
two new htlcs, 5 and 6, that use the same preimage and have the same
output value (in sats). This htlc set is used in tests that assert the
ordering of htlcs that have the same preimage and output value.
In this commit, an assertion is added to the bolt 3 commitment tx tests
that ensures that the local and remote balances add up to the expected
funding amount. Adding this assertion uncovered a borked test vector
which is also fixed in this commit.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
This commit modifies the channel state machine to be able to derive the
proper commitment and second-level HTLC output scripts required by the
new script-enforced leased channel commitment type.
This commit updates call-sites to use the proper dust limits for
various script types. This also updates the default dust limit used
in the funding flow to be 354 satoshis instead of 573 satoshis.
Previously whether or not to add test htlcs was implictly controlled by
a nil value of the HtlcDescs test parameter. With the conversion to
json, that nil value got lost.
The reason that the test still passed is because with the fee rate of
the no-htlc test case, the htlcs were trimmed. Also because in the test
json, balances are specified after applying htlcs, the test didn't fail
with a mismatching balance.
This commit changes the verification of our code against the spec test
vectors to use a more black box approach. It exercises the channel state
machine via its external interface as much as possible, making this test
more robust. A consequence of this is that the test now runs from the
'root' data from which the test vectors are also derived, meaning that
more code is covered too.
Running from the root data is also a preparation for _producing_ test
vectors for the new anchor commitment format. This will be a matter of
changing the channel type and recording the produced commitment and htlc
txes.
Previously the success transaction was skipped during verification. With
this commit, the proper preimage insertion is carried out, allowing the
success tx to be checked too.
Based on the current channel type, we derive the script used for the
to_remote output. Currently only the unencumbered p2wkh type is used,
but that will change with upcoming channel types.
createCommitmentTx would earlier mutate the passed commitment struct
after evaluating the htlc view and calculating the final balances, which
was confusing since the balances are supposed to only be *after*
subtracting fees.
Instead we take the needed parameters as arguments, and return the final
balances, tx and fee to populate the commitment struct in a proper way.
Instead of passing delays and dustlimits separately, we pass the correct
channel config to CreateCommitTx from the POV of the local party that
owns the commit tx.
To make it more clear which commitment we are actually creating, we
rename variables to denote local and remote, to prepare for the case
when both outputs might be delayed.
In this commit, we create a new chainfee package, that houses all fee
related functionality used within the codebase. The creation of this new
package furthers our long-term goal of extracting functionality from the
bloated `lnwallet` package into new distinct packages. Additionally,
this new packages resolves a class of import cycle that could arise if a
new package that was imported by something in `lnwallet` wanted to use
the existing fee related functions in the prior `lnwallet` package.
In this commit, we convert the existing `channeldb.ChannelType` type
into a _bit field_. This doesn't require us to change the current
serialization or interpretation or the type as it is, since all the
current defined values us a distinct bit. This PR lays the ground work
for any future changes that may introduce new channel types (like anchor
outputs), and also any changes that may modify the existing invariants
around channels (if we're the initiator, we always have the funding
transaction).
